i3
util.c
Go to the documentation of this file.
1 #undef I3__FILE__
2 #define I3__FILE__ "util.c"
3 /*
4  * vim:ts=4:sw=4:expandtab
5  *
6  * i3 - an improved dynamic tiling window manager
7  * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
8  *
9  * util.c: Utility functions, which can be useful everywhere within i3 (see
10  * also libi3).
11  *
12  */
13 #include "all.h"
14 
15 #include <sys/wait.h>
16 #include <stdarg.h>
17 #if defined(__OpenBSD__)
18 #include <sys/cdefs.h>
19 #endif
20 #include <fcntl.h>
21 #include <pwd.h>
22 #include <yajl/yajl_version.h>
23 #include <libgen.h>
24 
25 #define SN_API_NOT_YET_FROZEN 1
26 #include <libsn/sn-launcher.h>
27 
28 int min(int a, int b) {
29  return (a < b ? a : b);
30 }
31 
32 int max(int a, int b) {
33  return (a > b ? a : b);
34 }
35 
36 bool rect_contains(Rect rect, uint32_t x, uint32_t y) {
37  return (x >= rect.x &&
38  x <= (rect.x + rect.width) &&
39  y >= rect.y &&
40  y <= (rect.y + rect.height));
41 }
42 
44  return (Rect){a.x + b.x,
45  a.y + b.y,
46  a.width + b.width,
47  a.height + b.height};
48 }
49 
50 /*
51  * Updates *destination with new_value and returns true if it was changed or false
52  * if it was the same
53  *
54  */
55 bool update_if_necessary(uint32_t *destination, const uint32_t new_value) {
56  uint32_t old_value = *destination;
57 
58  return ((*destination = new_value) != old_value);
59 }
60 
61 /*
62  * exec()s an i3 utility, for example the config file migration script or
63  * i3-nagbar. This function first searches $PATH for the given utility named,
64  * then falls back to the dirname() of the i3 executable path and then falls
65  * back to the dirname() of the target of /proc/self/exe (on linux).
66  *
67  * This function should be called after fork()ing.
68  *
69  * The first argument of the given argv vector will be overwritten with the
70  * executable name, so pass NULL.
71  *
72  * If the utility cannot be found in any of these locations, it exits with
73  * return code 2.
74  *
75  */
76 void exec_i3_utility(char *name, char *argv[]) {
77  /* start the migration script, search PATH first */
78  char *migratepath = name;
79  argv[0] = migratepath;
80  execvp(migratepath, argv);
81 
82  /* if the script is not in path, maybe the user installed to a strange
83  * location and runs the i3 binary with an absolute path. We use
84  * argv[0]’s dirname */
85  char *pathbuf = strdup(start_argv[0]);
86  char *dir = dirname(pathbuf);
87  sasprintf(&migratepath, "%s/%s", dir, name);
88  argv[0] = migratepath;
89  execvp(migratepath, argv);
90 
91 #if defined(__linux__)
92  /* on linux, we have one more fall-back: dirname(/proc/self/exe) */
93  char buffer[BUFSIZ];
94  if (readlink("/proc/self/exe", buffer, BUFSIZ) == -1) {
95  warn("could not read /proc/self/exe");
96  _exit(1);
97  }
98  dir = dirname(buffer);
99  sasprintf(&migratepath, "%s/%s", dir, name);
100  argv[0] = migratepath;
101  execvp(migratepath, argv);
102 #endif
103 
104  warn("Could not start %s", name);
105  _exit(2);
106 }
107 
108 /*
109  * Checks a generic cookie for errors and quits with the given message if there
110  * was an error.
111  *
112  */
113 void check_error(xcb_connection_t *conn, xcb_void_cookie_t cookie, char *err_message) {
114  xcb_generic_error_t *error = xcb_request_check(conn, cookie);
115  if (error != NULL) {
116  fprintf(stderr, "ERROR: %s (X error %d)\n", err_message , error->error_code);
117  xcb_disconnect(conn);
118  exit(-1);
119  }
120 }
121 
122 /*
123  * This function resolves ~ in pathnames.
124  * It may resolve wildcards in the first part of the path, but if no match
125  * or multiple matches are found, it just returns a copy of path as given.
126  *
127  */
128 char *resolve_tilde(const char *path) {
129  static glob_t globbuf;
130  char *head, *tail, *result;
131 
132  tail = strchr(path, '/');
133  head = strndup(path, tail ? tail - path : strlen(path));
134 
135  int res = glob(head, GLOB_TILDE, NULL, &globbuf);
136  free(head);
137  /* no match, or many wildcard matches are bad */
138  if (res == GLOB_NOMATCH || globbuf.gl_pathc != 1)
139  result = sstrdup(path);
140  else if (res != 0) {
141  die("glob() failed");
142  } else {
143  head = globbuf.gl_pathv[0];
144  result = scalloc(strlen(head) + (tail ? strlen(tail) : 0) + 1);
145  strncpy(result, head, strlen(head));
146  if (tail)
147  strncat(result, tail, strlen(tail));
148  }
149  globfree(&globbuf);
150 
151  return result;
152 }
153 
154 /*
155  * Checks if the given path exists by calling stat().
156  *
157  */
158 bool path_exists(const char *path) {
159  struct stat buf;
160  return (stat(path, &buf) == 0);
161 }
162 
163 /*
164  * Goes through the list of arguments (for exec()) and checks if the given argument
165  * is present. If not, it copies the arguments (because we cannot realloc it) and
166  * appends the given argument.
167  *
168  */
169 static char **append_argument(char **original, char *argument) {
170  int num_args;
171  for (num_args = 0; original[num_args] != NULL; num_args++) {
172  DLOG("original argument: \"%s\"\n", original[num_args]);
173  /* If the argument is already present we return the original pointer */
174  if (strcmp(original[num_args], argument) == 0)
175  return original;
176  }
177  /* Copy the original array */
178  char **result = smalloc((num_args+2) * sizeof(char*));
179  memcpy(result, original, num_args * sizeof(char*));
180  result[num_args] = argument;
181  result[num_args+1] = NULL;
182 
183  return result;
184 }
185 
186 /*
187  * Returns the name of a temporary file with the specified prefix.
188  *
189  */
190 char *get_process_filename(const char *prefix) {
191  /* dir stores the directory path for this and all subsequent calls so that
192  * we only create a temporary directory once per i3 instance. */
193  static char *dir = NULL;
194  if (dir == NULL) {
195  /* Check if XDG_RUNTIME_DIR is set. If so, we use XDG_RUNTIME_DIR/i3 */
196  if ((dir = getenv("XDG_RUNTIME_DIR"))) {
197  char *tmp;
198  sasprintf(&tmp, "%s/i3", dir);
199  dir = tmp;
200  if (!path_exists(dir)) {
201  if (mkdir(dir, 0700) == -1) {
202  perror("mkdir()");
203  return NULL;
204  }
205  }
206  } else {
207  /* If not, we create a (secure) temp directory using the template
208  * /tmp/i3-<user>.XXXXXX */
209  struct passwd *pw = getpwuid(getuid());
210  const char *username = pw ? pw->pw_name : "unknown";
211  sasprintf(&dir, "/tmp/i3-%s.XXXXXX", username);
212  /* mkdtemp modifies dir */
213  if (mkdtemp(dir) == NULL) {
214  perror("mkdtemp()");
215  return NULL;
216  }
217  }
218  }
219  char *filename;
220  sasprintf(&filename, "%s/%s.%d", dir, prefix, getpid());
221  return filename;
222 }
223 
224 #define y(x, ...) yajl_gen_ ## x (gen, ##__VA_ARGS__)
225 #define ystr(str) yajl_gen_string(gen, (unsigned char*)str, strlen(str))
226 
227 char *store_restart_layout(void) {
228  setlocale(LC_NUMERIC, "C");
229 #if YAJL_MAJOR >= 2
230  yajl_gen gen = yajl_gen_alloc(NULL);
231 #else
232  yajl_gen gen = yajl_gen_alloc(NULL, NULL);
233 #endif
234 
235  dump_node(gen, croot, true);
236 
237  setlocale(LC_NUMERIC, "");
238 
239  const unsigned char *payload;
240 #if YAJL_MAJOR >= 2
241  size_t length;
242 #else
243  unsigned int length;
244 #endif
245  y(get_buf, &payload, &length);
246 
247  /* create a temporary file if one hasn't been specified, or just
248  * resolve the tildes in the specified path */
249  char *filename;
250  if (config.restart_state_path == NULL) {
251  filename = get_process_filename("restart-state");
252  if (!filename)
253  return NULL;
254  } else {
256  }
257 
258  int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
259  if (fd == -1) {
260  perror("open()");
261  free(filename);
262  return NULL;
263  }
264 
265  int written = 0;
266  while (written < length) {
267  int n = write(fd, payload + written, length - written);
268  /* TODO: correct error-handling */
269  if (n == -1) {
270  perror("write()");
271  free(filename);
272  close(fd);
273  return NULL;
274  }
275  if (n == 0) {
276  printf("write == 0?\n");
277  free(filename);
278  close(fd);
279  return NULL;
280  }
281  written += n;
282 #if YAJL_MAJOR >= 2
283  printf("written: %d of %zd\n", written, length);
284 #else
285  printf("written: %d of %d\n", written, length);
286 #endif
287  }
288  close(fd);
289 
290  if (length > 0) {
291  printf("layout: %.*s\n", (int)length, payload);
292  }
293 
294  y(free);
295 
296  return filename;
297 }
298 
299 /*
300  * Restart i3 in-place
301  * appends -a to argument list to disable autostart
302  *
303  */
304 void i3_restart(bool forget_layout) {
305  char *restart_filename = forget_layout ? NULL : store_restart_layout();
306 
309 
311 
312  ipc_shutdown();
313 
314  LOG("restarting \"%s\"...\n", start_argv[0]);
315  /* make sure -a is in the argument list or append it */
317 
318  /* replace -r <file> so that the layout is restored */
319  if (restart_filename != NULL) {
320  /* create the new argv */
321  int num_args;
322  for (num_args = 0; start_argv[num_args] != NULL; num_args++);
323  char **new_argv = scalloc((num_args + 3) * sizeof(char*));
324 
325  /* copy the arguments, but skip the ones we'll replace */
326  int write_index = 0;
327  bool skip_next = false;
328  for (int i = 0; i < num_args; ++i) {
329  if (skip_next)
330  skip_next = false;
331  else if (!strcmp(start_argv[i], "-r") ||
332  !strcmp(start_argv[i], "--restart"))
333  skip_next = true;
334  else
335  new_argv[write_index++] = start_argv[i];
336  }
337 
338  /* add the arguments we'll replace */
339  new_argv[write_index++] = "--restart";
340  new_argv[write_index] = restart_filename;
341 
342  /* swap the argvs */
343  start_argv = new_argv;
344  }
345 
346  execvp(start_argv[0], start_argv);
347  /* not reached */
348 }
349 
350 #if defined(__OpenBSD__) || defined(__APPLE__)
351 
352 /*
353  * Taken from FreeBSD
354  * Find the first occurrence of the byte string s in byte string l.
355  *
356  */
357 void *memmem(const void *l, size_t l_len, const void *s, size_t s_len) {
358  register char *cur, *last;
359  const char *cl = (const char *)l;
360  const char *cs = (const char *)s;
361 
362  /* we need something to compare */
363  if (l_len == 0 || s_len == 0)
364  return NULL;
365 
366  /* "s" must be smaller or equal to "l" */
367  if (l_len < s_len)
368  return NULL;
369 
370  /* special case where s_len == 1 */
371  if (s_len == 1)
372  return memchr(l, (int)*cs, l_len);
373 
374  /* the last position where its possible to find "s" in "l" */
375  last = (char *)cl + l_len - s_len;
376 
377  for (cur = (char *)cl; cur <= last; cur++)
378  if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
379  return cur;
380 
381  return NULL;
382 }
383 
384 #endif